WO2013117417A1

WO2013117417A1 - Pressure measuring glow plug

Info

Publication number: WO2013117417A1
Application number: PCT/EP2013/051067
Authority: WO
Inventors: Holger Scholzen; Wolfgang Koetzle; Janpeter Wolff
Original assignee: Robert Bosch Gmbh
Priority date: 2012-02-10
Filing date: 2013-01-22
Publication date: 2013-08-15
Also published as: US9541291B2; EP2812635A1; CN104094062B; JP5893759B2; DE102012202061A1; US20150013633A1; CN104094062A; JP2015506455A; EP2812635B1

Abstract

The invention relates to a pressure measuring glow plug comprising a housing (13, 14) in which a tubular heating element (21) for igniting a combustion mixture of an internal combustion engine and a pressure measuring unit (30) for detecting the pressure in the combustion chamber of the internal combustion engine are arranged. The tubular heating element (21) has a glow current contact (23) for an electric heating element (22). A pressure transfer element (50) is secured to the end of the tubular heating element (21) facing away from the combustion chamber, and transfers the combustion chamber pressure, which acts on the tubular heating element (21), to the pressure measuring unit (30). The pressure transfer element (50) is designed in a sleeve-like manner and forms a receiving chamber (51) for the glow current contact (23) of the heating element (22) on the tubular heating element side.

Description

Description title

pressure measuring glow

The invention relates to a Druckmessglühkerze for insertion into a

Cylinder head of an internal combustion engine having the features of the preamble of claim 1.

State of the art

Such Druckmessglühkerze is known from DE 102006008351 AI, in which a glow plug for igniting a combustion mixture of an internal combustion engine and a pressure measuring unit with a pressure sensor for detecting a combustion chamber pressure of the internal combustion engine are arranged in a housing. The glow plug is exposed to the combustion chamber pressure and transmits as

Pressure transducer, the combustion chamber pressure on the pressure sensor, wherein the

Pressure sensor between the acting as a pressure transducer glow pin and a support member is biased by a spring force of a flexurally elastic membrane by means of a clamping sleeve. The clamping sleeve is connected to the housing. The glow plug has a glow current contact for an electrical heating element housed in the glow plug, wherein the glow current contact is contacted with a Glühstromleitung. The Glühstromleitung is guided through the pressure sensor through to a terminal contact on the housing.

Disclosure of the invention

The invention with the characterizing features of claim 1 has the advantage that the Glühstromleitung is guided outside of the pressure sensor. Thus, the pressure sensor remains unaffected by the contact of the

Glow plug. Advantageous developments of the invention are possible by the measures of the subclaims.

Due to the fact that the sleeve-shaped pressure-transmitting element has a radial recess, there is sufficient free space for laterally leading out the glow-current line from the receiving space and for the continuation of the

Glühstromleitung created within the pressure measuring unit, wherein the

Glühstromleitung is contacted with a exposed outside the pressure measuring unit high current contact. For this purpose, the Glühstromleitung is guided in the axial direction within the pressure measuring unit on the pressure sensor and introduced by a in a support member for the pressure sensor

Carried out to finally outside the

Pressure measuring device to be contacted with the exposed high current contact. The exposed high-current contact is expediently formed on a glow module-side end face of a contacting unit.

An expedient embodiment of the Druckmessglühkerze is present when the pressure sensor is biased by the spring force of a flexurally elastic membrane, wherein the flexurally elastic membrane by means of a clamping sleeve with a

Supporting element, on which the pressure sensor is at least indirectly supported, is connected. The clamping sleeve in this case has an outer diameter D2, which is smaller than the outer diameter Dl of an outer support portion, so that there is an encircling gap between an inner diameter dl of the housing and the outer diameter D2 of the clamping sleeve. As a result, friction between the clamping sleeve and the housing is avoided, which would affect the accuracy of the pressure measurement. This also creates an annealing and pressure measuring module, in which the mechanical

Bias is adjustable for the pressure sensor outside the housing, whereby the mechanical preload of the pressure sensor is not affected in the subsequent assembly steps in assembling the Druckmessglühkerze.

embodiment An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description.

Show it:

Figure 1 is a sectional view through an inventive

pressure measuring glow,

Figure 2 is an enlarged sectional view through an annealing and

Pressure measuring module of Druckmessglühkerze invention

FIG. 1,

3 shows a detail X in Figure 2 and

FIG. 4 shows a partial sectional view of a support element-side end section of a pressure measuring unit according to FIG. 2.

The pressure-measuring glow plug illustrated in FIG. 1 combines a conventional glow plug for use in self-igniting internal combustion engines with an additional pressure measuring function of a pressure measuring device for detecting a combustion chamber pressure of the internal combustion engine. The pressure measuring glow plug essentially comprises an annealing and pressure measuring module 11 and a

Electronic module 12, which are at least partially accommodated in, for example, a multi-part housing 13. The housing 13 comprises several

Housing parts, such as a glow module housing 14, an electronics module housing 15 and a connector housing 16 for an electrical connector 42 for contacting a connector plug, not shown.

The glow and pressure measuring module 11 includes the actual components of a glow plug 20 for igniting the internal combustion engine and a pressure measuring unit 30 for combustion chamber pressure measurement. The glow pressure measuring module 11 comprises a glow plug 21 projecting from the glow module housing 14 on the combustion chamber side, which glow plug 21 projects with the projecting part into the combustion chamber

Internal combustion engine protrudes and thereby a pressure transducer for the im

Combustion chamber prevailing pressure forms. The glow plug 21 is in the present embodiment, a metallic glow tube in which an electric

Heating element 22, for example in the form of a heating coil is arranged, wherein the heating element 22 is connected to form a pole with the glow tube and to form the other pole with a Glühstromkontakt 23. The Glühstromkontakt 23 is at a combustion chamber facing away from the front side

Annealing pin 21 exposed out of the glow plug 21 in the form of a connecting bolt. Between glow tube and glow current contact 23, an electrically insulating sealing element 24 is further arranged. But it is also conceivable to perform the glow plug 21 as a ceramic heating element.

The electronic module 12 has a contacting unit 40, which comprises a carrier 41 for receiving a signal processing unit 70, for example an ASIC, and the plug housing 16. The carrier 41 and the

Plug housings 16 are made of an electrically insulating material,

for example, made of a plastic, wherein the carrier 41 is integrally formed in an axial longitudinal extent of the connector housing 16. As a result, the contacting unit 40 extends in the axial longitudinal extent of the

Pressure measuring glow.

The contacting unit 40 has an interface for contacting the annealing and pressure measuring module 11 on a glow module-side end face 43 of the carrier 41. The interface is formed by on the glow module side end 43 formed, exposed glow module side sensor contacts 45 to

Contacting the pressure sensor 31 and an exposed,

glühmodulseitigen high current contact 46 for contacting the

Glühstromkontakts 23 formed, wherein the contacting of the pressure sensor 31 via sensor lines 17 and the contacting of the Glühstromkontakts 23 via a Glühstromleitung 18 takes place.

In the carrier 41 and in the connector housing 16 further sensor-side connecting lines 47 and connector-side connecting lines 48 are integrated. With a radial distance from the sensor side and plug side

Provided connecting lines 47, 48 passes axially through the contacting unit 40 further comprises a high current line 49, the sensor side leads to the exposed high-current contact 46. On the plug side, the high-current line 49 continues through the plug housing 16 through to a high-current connection for the glow current of the glow plug 20 at the plug connection 42. The sensor-side and Plug-side connection lines 47, 48 and / or the high-current line 49 are expediently in the carrier 41 and in the connector housing 16th

cast. Appropriately, the on the glühmodulseitigen

End side 43 existing sensor contacts 45 formed by the integrally integrated in the carrier 41 sensor-side connecting lines 47. Accordingly, the high-current contact 46 likewise present on the sensor-side end face 43 is formed by the high-current line 49 integrated in the carrier 41.

The connections of the signal processing unit 70 are contacted by means of electrical connections 19 in each case with the sensor-side connection lines 47 and connector-side connection lines 48.

The contacting unit 40 is further at least partially surrounded by the tubular electronic module housing 15, wherein the carrier 41 is completely and the connector housing 16 is partially surrounded by the electronic module housing 15. On the electronics module housing 15, an external thread 44 for screwing into a cylinder head of the internal combustion engine is present. The electronics module housing 15 may be embodied in one piece or in several pieces.

The pressure measuring unit 30 is inside the glow module housing 14

housed, wherein the Glühmodulgehäuse 14 for receiving the

Pressure measuring unit 20 has an internal diameter dl. The

Pressure measuring unit 30 according to FIG. 2 comprises a sensor unit 30 ', a flexurally elastic diaphragm 60, a clamping sleeve 66 and a sleeve-shaped transmission element 50.

The sensor unit 30 'has a piezoelectric pressure sensor 31, a glow stick side pressure piece 32, a support member side pressure piece 33 and a support member 34, wherein the pressure sensor 31 between the glow pin side pressure piece 32 and the support member side pressure piece 33 is positioned and by means of the support member side pressure piece 33 on the support element 34 supported. The support element 34 has first recesses 35 for the passage of the sensor lines 17 and a second recess 36 for the passage of the glow current line 18. The sleeve-shaped transmission element 50 is arranged around an opening facing away from the combustion chamber of the glow plug 21 and fixedly connected to the glow plug 21. The sleeve-shaped transmission element 50 has a hollow-cylindrical receiving space 51 on the glow pin side and a sensor-side one

Pressure piece receptacle 52 on. Between the hollow cylindrical

Receiving space 51 and the sensor-side Druckstückaufnahme 51 is a stable partition 53 is formed with a sensor-side support surface 54. In the receiving space 51 of the high-current contact 23 projects with its remote from the combustion chamber end. Within the receiving space 51 is the

Glühstromkontakt 23 electrically connected to the Glühstromleitung 18. In the

Pressure piece receptacle 52 is the glow pin-side pressure piece 32 is received, such that it rests with a glow pin-side pressure receiving surface 57 on the support surface 54 gap-free.

In the cylinder wall of the sleeve-shaped transmission element 50, at least one radial opening 55 is provided, through which the

Glühstromleitung 18 is guided laterally outward. After the lateral guidance, the Glühstromleitung 18 substantially a 90 degree bend, so that the Glühstromleitung 18 in the direction of the high current contact 46 in

Lengthwise extension of the pressure measuring unit 30 is continued substantially axially. In the axial direction, the Glühstromleitung 18 between the

Sensor unit 30 'and the clamping sleeve 66 guided past the pressure sensor 31 and passed through the introduced in the support member 34 bushing 36 and then finally contacted with the high current contact 46 of the contacting unit 40. As a result, the Glühstromleitung 18 extends after the 90 degree bend between the sensor unit 30 'and the clamping sleeve 66 in the axial direction outside past the sensor-side portion of the sleeve-shaped transmission element 50, the glow stick side pressure piece 32, the pressure sensor 31 and on

supporting element-side pressure piece 33 and through the recess 36 of the

Support member 34 through to the high current contact 46th

By means of the flexurally elastic membrane 60 serving as a pressure transducer glow plug 21 is resiliently held within the Glühmodulgehäuses 14. The flexurally elastic membrane 60 has a glow pen side, inner

Support portion 61 and a housing-side, outer support portion 62. The Flexurally elastic membrane 60 is attached to the inner support portion 61 by means of a circumferential first weld 63 on an outer side 25 of the glow plug 21 and the outer support portion 62 by means of a single circumferential, second weld 64 on an inner side 26 of the Glümmodulgehäuses 14. The second weld 64 thereby forms a single attachment point on the outer support portion 62 for fixing the annealing and pressure measuring module 1 1 within the Glühmodulgehäuses 14.

The clamping sleeve 66 connects the flexurally elastic membrane 60 and the

Support member 34 within the Glühmodulgehäuses 14 rigidly, wherein the

Clamping sleeve 66 is attached at one end to the elastic membrane 60, for example by means of a first weld 67 and the other end to the support member 34, for example by means of a second weld 68. As a result, the receiving space 28 is sealed within the clamping sleeve 66 by means of the diaphragm 60 with respect to the combustion chamber of the internal combustion engine. As appropriate, it has been found that between the outer wall of the

Clamping sleeve 66 and the inner wall of the Glümmodulgehäuses 14 an annular gap 69 is formed. The clamping sleeve 66 in this case has an outer diameter D2, which is smaller than the outer diameter Dl of the outer support portion 62, so that the circumferential annular gap 69 between the inner diameter dl of the

Glühlodulgehäuses 14 and the outer diameter D2 of the clamping sleeve 66 results.

By means of the clamping sleeve 66, the pressure sensor 31 is held in the sensor unit 30 'between the transmission element 50 and the support member 34 by means of a bias, wherein the bias of the spring force of the flexurally elastic diaphragm 60 is applied. This creates the annealing and pressure measuring module 1 1 as a preassembled mounting unit, which the components of

Pressure measuring unit 30 and the glow plug 20 contains and with the

Sensor contact 45 and the high current contact 46 of the electronic module 12 is contacted. Subsequently, the glow module housing 14 is pushed over said assembly unit and with the electronics module housing 15th

welded. By means of the single weld 64 then the annealing and Pressure measuring module 16 by welding the outer support member 62 of the flexurally elastic membrane 60 to the inner wall 26 of the Glühmodulgehäuses 14 by means of another weld 64 is fixed to the Glühmodulgehäuse 14. This production sequence ensures that the bias voltage for the pressure sensor 31 is adjustable before the final assembly and is not affected by the further assembly step.

The pressure prevailing in the combustion chamber, the pressure on the as

Pressure transducer acting glow pin 21 exerts, causes due to the flexurally elastic membrane 60 of the glow plug 21 performs an axial movement relative to the housing 14 along the longitudinal axis. The bending elastic

Diaphragm 60 is resiliently formed with a flexural rigidity such that glow plug 21 can perform the required axial movement within housing 14 to transmit the pressure applied to glow plug 21 to pressure sensor 31.

Claims

claims

A pressure-measuring glow plug with a housing (13, 14) in which a glow plug (21) for igniting a combustion mixture of an internal combustion engine and a pressure measuring unit (30) with a pressure sensor (31) for detecting a

Combustion chamber pressure of the internal combustion engine are arranged, wherein the glow plug (21) has a Glühstromkontakt (23) for an electric heating element (22), and wherein at the end facing away from the combustion chamber end of the glow plug (21) a pressure transmission element (50) is fixed, which on the Glow pin (21) acting combustion chamber pressure on the pressure measuring unit (30) transmits, characterized in that the pressure transmission element (50) is sleeve-shaped and glow pin side a receiving space (51) for the

Glow contact (23) of the heating element (22) is formed, in which the

Glow plug (23) is contacted with a Glühstromleitung (18).

2. Druckmessglühkerze according to claim 1, characterized in that the sleeve-shaped pressure transmission element (50) has a recess (55) through which the Glühstromleitung (18) is guided laterally out of the receiving space (51) out.

3. Druckmessglühkerze according to claim 2, characterized in that the Glühstromleitung (18) guided within the pressure measuring unit (30) and with a outside of the pressure measuring unit (30) exposed high-current contact (46) is contacted.

4. Druckmessglühkerze according to claim 3, characterized in that the Glühstromleitung (18) in the axial direction within the pressure measuring unit (30) past the pressure sensor (31) and by a in a support element (34) for the pressure sensor (31) introduced implementation (36 ) for contacting with the exposed high current contact (46) out of the pressure measuring unit (30) out.

5. Druckmessglühkerze according to claim 3 or 4, characterized in that the exposed high-current contact (46) on a glow module-side end face (43) of a contacting unit (4) is formed.

6. pressure measuring glow plug according to claim 3, characterized in that on the support element (34) at least one further gap (35) for carrying out further electrical connections (17) for the pressure sensor (31) is formed.

7. Druckmessglühkerze according to claim 3, characterized in that the pressure sensor (31) is biased by the spring force of a flexurally elastic membrane (60) that the flexurally elastic membrane (60) by means of a

Clamping sleeve (66) with the support element (34) and by means of an outer

Support portion (62) on the housing (13, 14) is attached.

8. Druckmessglühkerze according to claim 7, characterized in that the clamping sleeve (66) has an outer diameter D2, which is smaller than the outer diameter Dl of the outer support portion (62), so that between an inner diameter dl of the housing (14) and the outer diameter D2 the clamping sleeve (66) results in a circumferential gap (69).

9. Druckmessglühkerze according to claim 7, characterized in that on the outer support portion (62) has a single attachment point (64) for attaching the pressure measuring unit (60) in the housing (13, 14) is formed.